As soon as the chott region is left and the higher ground is reached a different as well as a richer flora is encountered. Here diversity of topography favors diversity of plant life. On the reg near Biskra vegetation is especially abundant. Here, in fact, one passes through large thickets of _Tamarix_ and other species, and sees that the desert is much less intense than that in the south, especially in the region of the M’Zab, where in many respects the topography is similar. The kinds of plants also, as the list below will indicate, are different in the main from those farther to the south. Where the surface is most rolling we find _Tamarix_ sp. on the heights, _Zizyphus lotus_ in the hollows, and the following grasses: _Stipa tortilis_, _Hordeum maritimum_, and _Phalaris minor_. A salsolaceous shrub (_Arthrocnemon macrostachyum_) may be found in washes, _Nitraria_ and _Limoniastrum guyonianum_ on sandy places, and _Odontospermum pygmæum_ and _Anastatica hierochuntica_ occur between rocks. On clay flats one finds _Halocnemon strobilaceum_ and _Suæda vermiculata_, indicating the presence of salts. The preceding notes are in part from Massart. The following species are given by Doumet-Adanson as having been collected by him between Biskra and Touggourt: Savignya longistyla. Eremobium lineare. Lonchophora capiomontana. Monsonia nivea. Erodium pulverulentum. Fagonia sinaica. Haplophyllum tuberculatum. Lœfflingia hispanica. Paronychia nivea. P. cossoniana. Herniaria fruticosa. Zygophyllum album. Z. cornutum. Peganum harmala. Nitraria tridentata. Astragalus gyzensis. Ononis serrata. Ammodaucus leucotrichus. Cyrtolepis alexandrina. Anacyclus clavatus. Pyrethrum fuscatum. Nolletia chrysocomoides. Tanacetum cinereum. Ifloga fontanesi. Artemisia herba-alba. Anvillæa radiata. Atractylis flava. A. prolifera. Nonnæa micrantha. Lithospermum callosum. Heliotropium undulatum. Plantago ciliata. P. albicans. Limoniastrum guyonianum. Statice pruinosa. Echinopsilon muricatus. Traganum nudatum. Ephedra alata. Cutandia memphitica. Erythrostictus punctatus. Asparagus albus. Aristida pungens. =THE BISKRA REGION.= TOPOGRAPHY.[29]